I am sure I saw HW100 Cylinders on sale on Amazon this afternoon for £60 I thought I’d book marked it but alas I failed.
I am sure I saw HW100 Cylinders on sale on Amazon this afternoon for £60 I thought I’d book marked it but alas I failed.
Even the titanium alloy ones are welded tubes, so they all can split along that.
Last edited by krisko; 20-12-2018 at 07:59 AM.
Hi thanks for the reply.
You quote a wall thickness of 4.3mm @ a tensile strength of 245MPa. With these figures I get the deformation pressure as 569.5bar. While I completely concede that this is more than double the working pressure for normal operation, my problem is that on your listings you mention "Rigorously tested & certified to 650 bar with Rapid evacuation and rapid refill in a 10 times cycle, with no deformation or loss of structural strength recorded." This statement flies directly in the face of the 569.5bar deformation pressure calculation using Barlows formula. As scientifically it will deform at 569.5bar.
The answer your question "Why would we question a expert in there field in their test results?" Well, perhaps the fact that one of the cylinders split from end to end at 150bar? I would certainly be questioning them on both counts. You don't need to be an expert to reaslise that there is something wrong when tubes tested to 650bar are splitting at 150bar, do you?
regards
Goat
Last edited by Goatofmendez; 20-12-2018 at 05:07 PM.
It makes you think twice about buying after market parts. How many cheap and cheerful things have we all I’m sure bought and found them totally useless and or dangerous.
You do not often hear about bottles and or cylinders going tits up which is reassuring but and it is a big but these thing going wrong can quite literally kill some one.
Nothing is perfect and things do go wrong. It’s good to see that these cylinders are tested it ticks a box.
you mention "Rigorously tested & certified to 650 bar with Rapid evacuation and rapid refill in a 10 times cycle, with no deformation or loss of structural strength recorded." This statement flies directly in the face of the 569.5bar deformation pressure calculation using Barlows formula. As scientifically it will deform at 569.5bar.
regards
Goat[/QUOTE]
Hi Goat
Good the hear from you, hope you are enjoying the Christmas festivities.
To clarify and add to your workings out, Posted previously is "Material tensile strength is 245 Minimum MPa"
Minimum being the key word, You're quite right you should work of the Min fraction amount unless proven otherwise. The MPa is achieved when the chemical composition is formed (the makeup of the material is smelted/ cast) to be at a minimum of 245 Mpa upwards from 245MPa is guaranteed.
How to: Proving the material to be certified at a higher MPa
1.Raw material with the same chemical composition batch is acquired from a certified quality assured stock holder with full traceability provided. ISO
2. Machining takes place to a ISO standard
3. Visual inspection takes place for any defects in the machining process.
4. Finishing applied this is when the product is complete.
5. A random % of the products from the batch are sent for testing at a certified test house, this is where the true MPa is found.
If the item would burst at 569.5bar it would be at the minimum of the scale for that cast (batch) when smelted chemical composition when formed. However. If the testing houses findings are of that the 650 bar with Rapid evacuation and rapid refill in a 10 times cycle, with no deformation or loss of structural strength is recorded. This then is the certified MPa / upwards of 245MPa range. As stated the 245MPa is the starting point minimum of the Mpa range from the chemical composition that it was smelted too you can expect from the material. To get the True MPa as i know you are someone that would surely be interested in would be to test until destruction. The figure is then achieved. As 650MPa is over 2 x for Tench 3 x for HW100 Maximum that should be filled too.
6. Upon certification on the batch the tube is then constructed and tested in house to 260 bar (over stressing the tube can create a weakness)
Hope this clarifies the process
Worth covering our position again
This is one the main reasons we have stopped selling the tube only option there is too many factors to go wrong, having the right tools / experience / and safe way to test the cylinder after being built is a risk we are not willing to take. We sell them to Gun shops that are qualified to take the task on. However we feel it is too dangerous. We would like to see other suppliers follow suit or offer a service where they can send the tube to be changed at there facility so it is correctly done and checked safely.
As you grasp the dangers / pressures involved i am sure you will agree filling any tube in your hand is always dangerous and a risk that should not be taken, certainly after never being tested being built by a end user.
Less inexperienced users should be aware of the dangers of alterations modifications to all guns,with help & advice from the shooting community to protect our community from legislation / laws / licensees / annual test certificates from the Ban Everything lobbyists, Everyone's advice can help the whole shooting community.
Merry Christmas
Best Regards
Fenton
Last edited by Fenton Shooting; 21-12-2018 at 01:14 PM.
So what is the maximum MPa for 6082T6 Aluminium?
Still can't understand why the tube went pop at 150bar though. Also is it legal to send compressed air cylinders in the post? What postal method do you use?
thanks
They are cheaper to get, that’s why. Welded aluminium tubes are also common.
Everybody knows how to milk the hobbyist.
Blackmax You are absolutely right. Many here e.g. Goatofmendez are only complaining without
even knowing/using/testing these cylinders.
Fenton was the only distributor who answered very detailed and factual to all the accusations.
Ratworks or A&M didn't even write a single word here so a big thump up for Fenton.
Unfortunately my thread went in a direction which I didn't like at all. I esteemed the way Fenton
answered and I trust in their testing therefore I ordered a cylinder. And I am already sure
I will like it.
Merry Christmas
So the three of us who saw this know that the member it happened to is a skilled engineer of many years standing, and you are suspicious of the posts we have made?? The wall thickness at the point of fracture is less than 3mm.
Come and have a look if you don't believe us.
Merry Christmas.....
Nowhere to go ........in no hurry to get there; www.rivington-riflemen.uk----- well I suppose it is somewhere to go.... founded by I.J. - let down by the tainted blood scandal